A sustainable architecture expert has called for more government investment in the construction industry in order for more carbon-neutral homes to be built in the UK.Mark Siddall of Dewjo'c Architects - the firm currently working on the Middlehaven zero-carbon development project - is expected to speak at Middlesbrough Town Hall about how the government can do more to create energy-efficient building regulations.He told the Evening Gazette that the concept of zero-carbon homes in the UK needs a standard definition, as different government groups appear confused as to what constitutes a carbon-neutral property.He said: "Two Government departments have differing definitions of what constitutes a 'zero carbon' home - the Treasury definition states that a gas supply can not be used … whilst the Department for Communities and Local Government, via the Code for Sustainable Homes, suggests that gas supply is acceptable."Mr Siddall added that there may be a long way to go before so-called zero-carbon homes actually do not produce carbon emissions, as some still use energy produced by fossil fuels.In Middlehaven, an award-winning 750-home zero-carbon development project is in the works, funded by a £200 million investment. Homes in the development will be powered by renewable energy and will receive their hot water from a biomass boiler.